What You Need to Know Before Shooting Slow Motion with the FS700, and Some Recent Examples

If you already bought an FS700, or you've been waiting on the sidelines so far, there is a big issue with slow motion that many who've shot with Phantom cameras might already be familiar with: flicker. Now that film sets are littered with different types of fixtures, it's important to understand how shooting slow motion under different light sources can induce some amount of flicker. Certain fixtures produce more flicker than others (especially at different shutter speeds), but in the video below, Hello World Communications takes a look at some of the most popular fixtures for film lighting and how they deal with flicker. Also embedded below, check out some recent examples from Luke Neumann and Tony Reale.

Obviously shooting in daylight shouldn't really cause any flicker as there aren't any electrical frequencies to deal with, but if you have to light, Tungsten may be the most consistent option across all brands. Many HMI and florescent fixtures produce flicker at varying degrees thanks to the ballasts that are used to limit the amount of current running through the lamp. It's certainly possible to find flicker even at normal framerates, it just depends on the fixture (usually florescent), age of the lamp, and whether or not it is working correctly.

Luke Neumann, a frequenter of this site, spent a few days with the camera and produced some interesting results on a very small budget. Here is the final product followed by his production diaries:

Sony has truly lowered the bar for slow motion, and while it's likely we will see a lot more on the web over the next few months, it's another important step in the democratization of filmmaking. Even though one tool doesn't have to be good at everything, it's fairly convenient to be able to buy one camera that has a lot of dynamic range, is great in low-light, has a sharp image, and can record some spectacular slow motion.

Your Comment

Comment *

Leave this field blank

13 Comments

This still remains one of the most interesting cameras to be released this year. Was just wondering, does anyone know when it will be officially released in europe? Most retailers I've seen either do not specify a release date or have a tenuous '25-30 days' margin.

Also, has anyone tried twixtoring the 240fps output to see the results? I've read that the final file produced is 60p with the footage already slowed down (something which effectively enables recording to an external device), which should yield fairly clean results if further slowed down using twixtor.

Thanks for the shout out Joe. Good point about an all in one camera. The FS700 is solid across the board, some people just don't like the Sony image at all. I was really impressed and would love more time with it to see if a more "filmic" look is possible. Going from this back to the GH2 makes me realize just how much dynamic range it has though, it's pretty insane.

Luke, really nice slo-mo video! Entertaining as well. Looks like you guys had lots of fun. The FS700 is a very sweet camera for the money. Sony fixed the two obvious problems with the FS100 - built in ND's and SDI. The slo-mo is amazing for the price point. Even the 480 fps at 720P looks pretty good if you need it. I would love to see how well ultra slo-mo (1000 - 2000 fps) could be simulated using 240 fps and Twixtor. Much less frames to simulate than 60 fps. I enjoyed the diaries as well.

Could someone please interpret the flicker video for us? I see flicker in the HMI version but not much on the other lights. I see the differences in blur (the fan especially) and strobing (the bubbles) from the different shutter speeds keeping the frame rate constant. I see how poor vimeo compression is. I see how nice tungsten lighting is, how kino overdoes the minus green in combatting their green spike, and how ugly LED arrays are.

Are there a lot of flicker differences my laptop isn't making clear over vimeo?

Peter, I had difficulty seeing distinct flicker as well. I'm sure that internet viewing is more forgiving of the flicker. When it's subtle, it can also be hard to notice flicker on the set, especially if the viewing monitor is small or there is a lot of ambient light falling on the monitor. Whenever a flicker situation is possible, I recommend looking at a static shot (no actors or movement) and study a waveform monitor or histogram. Look for vertical or horizontal "breathing." In the test video shown in this post, the HMI lighting "should" have the least flicker (other than tungsten) since square wave (flicker free) ballasts were used. Tungsten light is obviously the safest artificial light. However, it is not very practical in shots that cover a wider area. Large units like 5K's or 10K's are needed and they require more juice than household power can provide. Also, light "quality" can be compromised if only direct "hard" is used. HMI's with square wave ballasts could be the best lighting option for flicker "protection" and output efficiency. However, frame rates above 120 fps are more likely to have flicker. The best process is to test various shutter speeds and watch a waveform or histogram carefully. Shutter speeds that are multiples of 60 (hertz) should be the safest for high speed. Kinoflos also use square wave ballasts - but the are generally not bright enough at high speeds to be practical. For an excellent article about the "math" and cause of flicker issues, see excellent article by Art Adams: http://provideocoalition.com/index.php/aadams/story/rolling_shutter_and_...

For what it is worth I did a shoot recently using Tungsten (Red Heads) and mixed with fluorescents (Kinos + ePhotonics) balanced to Daylight and some natural daylight. I experienced zero flicker. So I'm thinking it's more of a concern with HMI.

Noise shooting 2K RAW at 240fps is a potential deal breaker. The noise issues are horrible and consistent if recording to an external recorder via SDI. You need to shoot with bright diffused daylight and even then it will haunt you. This camera suffers from the lack of the low pass filter which Sony eventually fixed the F5/F55 for an additional "upgrade" price. You can fix it with noise filters, and to tell you the truth it looks nicer overall and more cinematic if one processes it this way. What was a fix for noise issues turns into a method you can tweak with to make your images look more like 35mm film; pixels are smoothed by the process in eliminating noise. No more too digital sharp, hello a cinematic look. Try it. Incidentally, the FS700 loses its dynamic range in 4K RAW and requires bang on over-exposure by 1 to 1.5 stops, or the noise from its flavour of sensor will dance in the darker areas creating little visual joy. It's a great camera for the price, if you know how to shoot it. But it's really unforgiving if you don't. It is performs in spectacular fashion when you shoot S-Log2 and super-sample down from the 4K sensor and record to an Odyssey Q7 as 1080 ProRes HQ - some of best HD footage capture by any camera out there in this config.

Get your FREE copy of the eBook called "astonishingly detailed and useful" by Filmmaker Magazine!
It's 100+ pages on what you need to know to make beautiful, inexpensive movies using a DSLR. Subscribe to receive the free PDF!